A track-type mobile machine utilizes tracks located at either side of the machine to propel the machine. The tracks each include a chain having links pinned end-to-end to form a loop that extends around a drive sprocket and one or more idler wheels, and ground-engaging pads connected to each pair of links in the chain. A ground-engaging pad, together with a pair of links, is commonly referred to as a crawler shoe. In some embodiments, the crawler shoe is a single cast and/or forged component made of steel. During operation, each crawler shoe encounters forces cause by the weight of the machine and torque from the engine for driving the machine. The forces are transmitted through the crawler shoes and into the ground surface, thereby creating traction to propel the machine.
Over time, the forces acting on the crawler shoes can cause localized wear and plastic deformation, leading to a shortened life span of the crawler shoes. Steel crawler shoes are sometimes hardened using heat treating processes such as quench and tempering to resist wear and prolong the life of the crawler shoes. Multiple heat treatment steps are typically used to achieve a minimum hardness at particular depths below the surface of crawler shoes. An example of this type of hardening process is disclosed in U.S. Pat. No. 7,040,080 of Okawa et al. that issued on May 9, 2006. However, hardening processes that involve multiple tempering and/or other heat treating steps require high energy inputs and are expensive, which increases the price of crawler shoes to the end user.
The disclosed crawler shoes are directed to overcoming one or more of the problems set forth above.